Tool to preset contact stabs on connection blocks



Feb. 27, 1968 B. H. SCHWARZ TOOL TO PRESET CONTACT STABS ON CONNECTIONBLOCKS Filed July 27, 1965 2 Sheets-Sheet 1 .w IIII'II'I l [Ill-II N 2Sheets-Sheet 2 [I urirliiili B. H. SCHWARZ TOOL TO PRESET CONTACT STABSON CONNECTION BLOCKS Feb. 27, 1968 Filed July 27, 1965 v United StatesPatent Ofifice 3,370,453 Patented Feb. 27, 1968 3,370,453 TOOL T PRESETCONTACT STABS 0N CQNNECTION BLOQKS Bernhard H. Schwarz, Montvale, N.J.,assignor to Consolidated Edison Company of New York, Inc, New York,N.Y., a corporation of New York Filed July 27, 1965, Ser. No. 475,163Claims. (Cl. 72-479) ABSTRACT OF THE DISQLGSURE Hand tool havingelongated shank with fluted tip at lower end for forcing into stab slotsto spread same; guide sleeve slidably mounted on shank to align shankwith stab.

This invention relates to a method and apparatus for presetting contactstabs mounted on electrical contacts and more particularly in one formthereof to a tool for realigning slots in male contact stabs onelectrical connection blocks. Among many possible uses, this inventionis particularly adapted for use in connection with a removableinterrupting element for use with withdrawable air-blast circuitbreakers to provide reliable control and protection of power systems. Inthis type of installation one connection block is provided with aplurality of spaced male contact stabs and a second mating connectionblock is provided with a like plurality of female contact members.

Heretofore, considerable difiiculty has been experienced with contactstabs on connection blocks due to the fact that after the contact stabhas been pressed into engagement with the corresponding female contactmember one or more times, there is a tendency for the female contactmember to permanently deflect or compress the stab member. Whileresiliency exists in the stab member tending to return the prongs totheir original positions, a certain permanent deflection occurs. As aresult of this deflection, the stab members do not properly engage theircorresponding female contact members, thereby causing unreliable andpoor connections. A plurality of stabs and a corresponding plurality offemale members tends to accentuate the problem.

Heretofore attempts have been made to rectify this diiliculty, but theyhave not been entirely successful. Operators have inserted screwdriversinto the slots in the male stab in an attempt to preset the spacing, butthis is haphazard, inaccurate and unreliable.

Briefly, this invention contemplates the provision of a tool forpresetting stabs mounted on connection blocks comprising an elongatedshank which has a fluted portion at the lower end thereof and a collardisposed adjacent the fiutes. The flutes are formed by a plurality ofraised faces, and a lower tip is formed by an upwardly increasing taperat the lower end of the shank. Also, the raised faces have upwardlyincreasing widths for engaging the slots in said stabs. A handle may beconnected to the upper end of the shank for manipulating the tool. Anelongated guide sleeve encompassing the lower end of the shank isprovided having one portion thereof disposed closely adjacent the shankand another portion thereof engaging said connection block for aligningthe shank with respect to the stab to be preset. The collar isengageable with the end of the stab to limit the downward travel of theshank during operation of the device.

The invention in another form thereof comprises a method of presettingcontact stabs by inserting a guide sleeve into the recess surroundingthe contact stab in a connection block, and lowering a fluted shank intosaid sleeve until the tip engages the end of the stab. Thereafter, themethod comprises twisting the shank a partial revolution until itregisters with the slots, and thence, downwardly pressing the shank intothe slots until a collar mounted on the shank engages the end of thestab, and finally withdrawing the shank and sleeve from the sopresetstab.

An important feature of the invention is the provision of a new andimproved tool to preset the slots in contact stabs mounted on connectionblocks which overcomes the aforementioned difficulties.

Another feature of this invention resides in the provision of a tool topreset contact stabs which is of simple well-balanced construction,which is readily and economically fabricated and assembled on a massproduction basis, and which is sturdy and durable, being capable of along service life of severe usage.

A further feature of the invention resides in the provision of a new andimproved tool for realigning the slots in electrical male plugs whichoperates easily, accurately and reliably.

These and other objects, features and advantages of the invention willbecome more fully apparent from the following detailed description ofthe invention when taken together with the accompanying drawings inwhich:

FIGURE 1 is a perspective view showing a mating pair of connectionblocks one of which has a plurality of male contact stabs mountedthereon and the other has a corresponding plurality of female connectingmembers mounted thereon;

FIGURE 2 is a vertical sectional view through the center of a contactstab and a female contact member in engagement one with the other;

FIGURE 3 is a plan view showing a pluralityof contact stabs mounted on aconnection block;

FIGURE 4 is a vertical sectional view taken along the line 44 of FIGURE3 and showing a tool, constructed in accordance with the invention,positioned in engagement with the upper end of a stab;

FIGURE 5 is a fragmentary vertical sectional view showing a tool,according to the invention, in operative position for realigning theslots in an electrical male plug or stab;

FIGURE 6 is a fragmentary perspective view showing the fluted tip of theshank of the tool and including the collar; and

FIGURE 7 is an end view of the shank of the tool showing the tipthereof.

Referring in particular to FIGURE 1, there is shown a male connectionblock 10 and a corresponding female connection block 12, the maleconnection block having a plurality of contact stabs or male plugs 14and the female connection block 12 having a plurality of female contactmembers 16. The connection block 10 is mounted on a circuit breaker 17,FIGURES 3 and 4, by means of lugs 18 having bolt holes 20 for bolts 21.

As best seen in FIGURE 2, the female contact member 16 is mounted in ahexagonal recess 22 in the connection block 12, said recess beinginterrupted by a shoulder portion 24. The female member 16 is secured inposition by means of a locking member 26 which has a shoulder portion 28engageable with the shoulder 24 of the connection block 12. The lockingmember 26 has a longitudinally extending threaded portion 30 which fitsinto the threaded portion 32 of the female member 16. When assembled thelocking member 26 threadably engages the female member 16 to clamp theshoulder 24 of the contact 12 between shoulders 28 and 34.

Still referring to FIGURE 2, the female contact member 16 is providedwith a recess 36 for receiving the stab or male contact member 14, asshown. The stab or male contact member 14 is mounted in a hexagonalrecess 37 and is secured to the connection block 10 by locking member 38which is identical to locking member 26.

Accordingly, locking member 38 has a threaded portion 40 which engagesthe threaded portion 42 of the stab 14 so that shoulder 44 and shoulder46 of the male contact member engage shoulder 48 of the connection blockit As best seen in FIGURE 3, each of the stabs or male contact members14 is provided with a plurality of longitudinally extending slits orslots 50, two being shown in the form of a cross.

Usually the stab member is fabricated from resilient material, andhence, tends to return to its original configuration subsequent toremoval thereof from the female member. However, after one or morecontacts have been made the stab tends to take a permanent set in adeformed configuration, thereby closing or partially closing the slot50. A slot is shown at 52, FIGURE 3, in its original configuration andis shown at 54 in its closed or deformed configuration.

According to the invention, a tool 56 for presetting the slots in thecontact stabs 14 comprises a shank 53,

FIGURES 4 and 5, having a handle 60 connected to the upper end thereofas at 62 for manipulating the tool. The lower portion of the shank 58 isprovided with a plurality .of raised faces 64, FIGURES 47, formingflutes 66 therebetween, and includes a lower tip 68 formed by anupwardly increasing taper. Further, the raised faces 64 have upwardlyincreasing'widths for a purpose which will be discussed more fullyhereinafter.

As best seen in FIGURE 6, the shank ssie provided with a collar 70disposed adjacent the fluted portion. This collar serves to limit thedownward travel of the shank 58 during operation of the tool as shown inFIG- URE 5. 1

Referring to FIGURES 4 and 5, an elongated bushing or guide sleeve 72encompasses the lower end of the shank 58. This sleeve includes anupperportion 74 and a lower portion 76 which are interconnected as by meansof a press fit shown at 78. The upper portion 74 has a reduced insidediameter which loosely engages the shank 58, as at'79, thereby aligningthe guide sleeve 72 with respect to the shank 58. The lower portion 76of the sleeve 72 e is provided with a lower projection 80 of reducedoutside diameter which slidably fits into the recess 37 encompassing thestab 14, as shown in FIGURES 4 and 5, to align the sleeve 72 withrespect to the connection block 10, thereby aligning the shank 58 withrespect to the stab 14. It is noted that after assembly the freelyslidable shank 58 is confined within the sleeve 72 by the upper shoulder82and the lower shoulder 84 of the sleeve 72 between which the shank isfree to move until its collar 79 abuts either of the same.

In operation, when the slits or slots become pinched through use asindicated at 54, FIGURE 3, the tool 56 is brought into position. Thesleeve 72 is placed over the stab 14 as shown in FIGURE 4 so that thelower projection 80 thereof extends into the recess 37 of the connectionblock 10, as shown. The shank 58 is thence lowered until the tip 68engages the end of the stab 14, as shown in FIGURE 4. Thereafter, theshank 58 is rotated a partial revolution by means of handle 60, untilthe raised surfaces 64 register with the slots 54. Then the shank 58 ispressed downwardly into the slots until the collar '70 engages the endof the stab 14 as shown in FIGURE 5. It will be appreciated that theraised faces 64 have upwardly increasing widths so that the depth towhich the shank is pressed determines the width of the slot in the stab14. Accordingly, the upper end width of the raised faces 64 determinesthe width to which the slots will be widened, and the collar 70accurately determines when full insertion of the faces 64 has been made.Actually, due to the resiliency of the material, it is preferable toopen the slots to a width slightly in excess of the final desired widthin order to allow the material to resiliently return a short distanceafter removal of the tool, and for this reason the width of the taper atthe upper end of the faces 64 is made slightly oversized with respect tothe Y 4 I desired, normal spacing of the slots 5%. Thereafter, the tool56 is Withdrawn from the stab 14 by means of upward movement of thehandle 60 so as to lift the shank 58 until the collar '76 engages theshoulder 82 of the sleeve. The tool is then withdrawn entirely from itsoperative position.

Thus has been described a tool for presetting contact stabs onconnection blocks which achieves all of the objects of the invention.

What is claimed is:

1. A tool to preset a contact stab mounted on a connection block, saidstab having a plurality of open slots, said tool comprising anelongatedshank, a fluted tip at the lower end of said shank presentingaplurality of flutes corresponding in number and arrangement to saidplurality of stab slots for respectively engaging the same, and anelongated guide sleeve mounted for axial slidable movement on said shankadjacent its said lower end, said sleeve having a portion for" engagingsaid connection lock to. position said shank in alignment with saidstab, whereby said flutes are guided in their said engagement with saidstab slots; e

2. A tool to preset a male contact stab mounted on a connection block,said stab having a plurality of longitudinally arranged, open endedslots, said tool comprising an elongated guide sleeve, an elongatedshank longitudinally slidable within saidg uideslceve, a fluted tip atthe lower end of said shank, a portion of saidsleeve disposed closelyadjacent said shank for aligning said sleeve with respect to said shank,the lower portion of'said sleeve being engageable with said connectionblock for aligning said shank with respect to said male contact stab tobe preset. i

3. A tool for presetting longitudinally arranged open ended slots in anelectrical male contact stab mounted on a connection block, said toolcomprising an elongated guide sleeve, an elongated shank longitudinallyslidable within said guide sleeve, a fluted tip at the lower end of saidshank, a collar disposed adjacent said flutes, a portion of said sleeveabove said collar being disposed closely adjacent said shank foraligning said sleeve with respect to said shank, the lower portion ofsaid sleeve being engage'able with said connection block for aligningsaid shank with respect to said male stab to be preset, and handle meansfor said tool.

4. A tool for presetting longitudinally arranged, open ended slots in anelectrical male stab mounted in a recess on a connection block, saidtool comprising an elongated guide sleeve, an elongated shank,longitudinally slidable within said guide sleeve, a fluted tip at thelower endof said shank, a collar disposed adjacent said flutes, a handleconnected to the upper end of said shank for manipulating said tool, aportion of said sleeve above said collar being disposed closely adjacentsaid shank for aligning said sleeve with respect to said shank, thelower portion of said sleeve extending below the fluted tip of saidshank and being longitudinally slidable within the recess in saidconnection block for aligning said shank with respect to said male stabto be preset, and said collar being engageable with the end of said malestab to limit the downward travel of said shank during operation of saidtool.

5. A tool to preset longitudinally arranged and open ended slots in acontact stab mounted on a recessed shoulder on a connection block, saidtool comprising an elongated guide sleeve having a lower projection, anelongated shank longitudinally slidable within said guide sleeve, ahandle connected to the upper portion of said shank, a fluted portion atthe lower end of said shank, the number of flutes corresponding to thenumber of slots in each contact stab, said fluted portion'having a lowertip and an upwardly increasing taper, a portion of said sleeve engagingsaid shank, and said lower projection engaging said recessed shoulder onsaid connection block for aligning said shank with respect to said stab.

6. A tool to preset open slots in a stab mounted on a connection block,comprising an elongated shank, a plurality of raised faces formingflutes at a lower end of said shank for respectively engaging said stabslots, each of said raised faces having increasing width in upwarddirection relative to said shank, and said lower end of the shankincluding a lower tip having upwardly increasing taper and a guidesleeve slidably mounted on said shank and having means for engaging saidconnection block, whereby said flutes are guided in their saidengagement v'ith said stab slots.

7. A tool to preset slots in 'a stab mounted on a connection blockaccording to claim 6 wherein a collar is disposed adjacent said fluteson said elongated shank, said collar being engageable with the end of acontact stab to limit the downward travel of said shank during operationof said tool.

8. A tool to preset slots in a stab mounted on a connection blockaccording to claim 6 wherein the upwardly increasing widths of saidraised faces are wider than the respective desired opening of therespective slots.

9. A tool to preset longitudinally arranged, open ended slots in acontact stab mounted on a recessed shoulder on a connection blockcomprising an elongated guide sleeve, an elongated shank longitudinallyslidable within said guide sleeve, a handle connected to the upperportion of said shank, a plurality of raised faces forming flutes at thelower end of said shank, each of said faces corresponding to a slot insaid contact stab, said lower end of said shank having a lower tipformed by an upwardly increasing taper, the raised faces having upwardlyincreasing widths, 'a collar disposed adjacent said flutes, a

portion of said sleeve above said collar being disposed closely adjacentsaid shank for aligning said sleeve with respect to said shank-the lowerportion of said sleeve extending below the fluted tip of said shank andengaging the recessed shoulder on said connection block adjacent thecontact stab for aligning said sleeve with respect to said shank andwith respect to said contact stab to be preset, said collar beingengageable with t1 e end of said contact stab to limit the downwardtravel of said shank during operation of said tool.

16. A tool for presetting a contact stab mounted on a connection block,said stab having a plurality of slots, said tool comprising an elongatedguide sleeve having an upper shoulder and a lower shoulder, an elongatedshank freely, longitudinally slidable within said guide sleeve, a flutedtip at the lower end of said shank, a collar carried by said shank, saidshank being confined within said sleeve by said collar engaging saidupper shoulder in one direction and by said collar engaging said lowershoulder in the other direction, whereby said fluted tip remainsprotectively disposed within said sleeve in all positions of said shankwith respect to said sleeve.

References Cited UNITED STATES PATENTS 9/1931 Evans 29271 X 4/1963 DeLancey 72479 X

